We had a very inconsistent experience with service from the 401k Department at ML. Being a Managing Director in the field; I had very little control over the operation of departments in NY. At the time we were being serviced by a phone bank of 401k staff, some good, and some bad. I asked if our office could be serviced by one qualified person. We selected the person and after some negotiation, it was agreed.
Everything changed. Service was great; everybody had the name of our service representative. When she was promoted she recommended the next person for our office.
Although this seems obvious, this was a huge breakthrough for us. The personal accountability that was brought to the problem dramatically changed the level of service.
The entire 401k department soon switched to this personal accountability model and the quality of service improved immediately.
When you are facing quality of service issues, check to be sure that a staff member owns both the client and the problem. There should never be figure pointing (not my job). If your company is organized with phone banks, consider changing to this model and watch service improve.